Apparatus for pulsation elimination in fluid streams



June 2.8-, 1949.

F. M. STEPHENS ETAL APPARATUS FOR PULSA'IION ELIMINATI IN FLUID STREAMS Filed Aug. 5, 1946' Psaseafnaefms l msiriirs'ron msA'rroN sur Anon.

FosferlMrStphens, Los Angeles, and Cecil F. Yates. North Hollywood. Calif., assignora to The Fluor Corporation, Ltd., Los Angeles. Calif., a corporation ot California Application August 5, 1946, Serial No. 688.552

This invention has to do with apparatus for the removal of pressure pulsations occurring in liquid streams, and relates particularly to improvements in certain type of systems disclosed in copending application Serial Number 631,192, tiled-November 27, 1945, on Pulsation elimination inliquid streams.

In certain of its major aspects, the .invention relates to pulsationeliminating apparatus employing a pair ofvessels communicable with the liquid-carrying line and containing gas which undergoes compression and expansion in response to the transmission respectively of increasing and decreasing line pressures. Basically, the general combination contemplates the provision of means, or an appropriate resistance, in the pulsating liquid line, for shifting the normal phases of the pulsations being transmitted to one of the chambers. Such resistance preferably, though typically, may take the form of an elongated restriction or inductance in the line between its connections with the gas-containing vessels.

One primary object of the invention is to provide a unitary assembly utilizing a body structure within which is accommodated the gas containing vessels and their line connections, as well as the restricted passage or inductance section of the line. plates replacement of the vessels within the housing in a manner rendering them directly accessible for gas charging, while maintaining the remaining parts and connections in compact relation within the body.

A further `object of the invention is to provide such connections and valve controls as will permit isolation of either or both vessels from the line, and withdrawal vof liquid from the vessels so that the latter may `be charged with gas at an accurately determinable base pressure.

All the features and objects, as well as the details of an illustrative embodiment of the invention, will be fullyunderstood from the following description of the accompanying drawing which shows the apparatus in cross-s-ection taken through the body. y f

Referring to the drawing, the apparatus comprises a tubular body I0, suitably mounted or supported, as by a pair of legs II. Each end of the body carries a removable cover I2 secured to the body anges I3 by bolts I4, each cover carrying an annular guard I5y for protection of the gas vessel iittings.

The. body I0 contains a pair of gas-charged vessels I6, preferably of spherical form, having `their outer or neck -portions I1 received within openings I8 in the covers I2. Each vessel I8 contains a bladder-like flexible diaphragm I9, shaped in accordance with the vessel so that when fully distended the diaphragm will conform to the 2I through which gas may be charged into and Particularly the invention contemmaintained under a desired pressure within the diaphragm chamber 22. At this point it may be observed that the gas pressure in chamber 22 will be so related to the pressure in the liquid chamber 23 at the opposite side of the diaphragm, as to maintain the latter in a condition of deflection, for example as shown in the sectionally illustrated vessel,` permitting displacements of the diaphragm causing compression and expansion'cf the gas in chamberD-ZZ, in response respectively to increasing and decreasing pressures in the liquid chamber 23.

Pipes 24 are illustrative of va line. carrying liquid in a condition of pulsating ilow, as created for example by piston type pump from which pressure pulsations are transmitted' by4 the liquid stream. Pipes 24 have flange connections at 25 with closed end pipes 26 extending laterally through the wall of the body into its interior. The liquid chambers 23 in the vessel I6 are connected with the liquid line by way of pipes 21 each containing a valve 23, accessible through an opening 29 in the body, and a T-tting 30 to which is connected the liquid draw-off line 3| carrying an outsidevalve 32.

The pipes 26 are in communication through a type of connection 33 presenting resistance to the liquid ow from one to the other of the pipes, and therefore imposing on the liquid stream a pressure drop in accordance with the nature of the resistance. As will later appear, this resistance may be one or' diierent types (by analogy to electrical lter systems) although preferably it is made in the form of an inductive type resistance comprising an elongated pipe 34 of considerably smaller diameter than the line size, to present a restricted fluid passage 35. Being ordinarily of greater length than thedistance between the pipes 2B, pipe 34 may be formed as a coil extending about the pipes 2KB and connecting at 36 therewith, substantially as shown.

The vessels I6 serve essentially as variable liquid volume capacitances exerting converting in- :fiuencesl on the pulsations transmitted by the liquid flowing inthe line 24. This converting effect results from the ability of the capacitance, be-

cause of its responsiveness to increasing or decreasing liquid pressure, to exert a phase shifting influence on the line stream pulsations by presenting to each positive pulse, a reduced or negative compensating pressure, and kto each negative pulse an increased or positive compensating pressure. With the phases thus compensated,

the tendency is toward regularlz'ation of the liquid determined to exert a. pulsation phase shifting effect, thus introducing a time factor in the phase sequence. Briefly, the general effect of the inductance type restriction is to create a kenetic energy condition retarding, for example, a positive pressure surge while simultaneously increasing the stream velocity, and the discharge of the accelerated stream into the capacitance chamber so that the resulting energy of the phase-shifted pulse coincides with a negative pressure condition or pulse in the chamber, to produce an average or substantially constant resultant pressure. 'I'he length and diameter of the inductance connection may be varied in accordance with the particular requirements of individual installatiois.

As a typical example, the appartus as shown in the drawing has effectively eliminated pulsations from a liuquidl stream being discharged through line 24 at the rate of about 50 cycles per minute by a piston type pump operating at a frequency of 25 strokes per minute. The capacitance I6 formed by spherical shells of 8 inches outside diameter, and the inductance connection 33 consisted of a 1 inch pipe 3l having a length of 6 feet.

Valves 28 may be closed when for any reason it is desired to isolate the capacitances from communication with the liquid line. Provision is made by the valve lines 3| for withdrawing all liquid from the chambers 23, or for relieving thel pressure at the liquid side of the diaphragms, so

that the chambers 22 may be charged with gas at accurately determinable pressure, initially resulting in deflection of the ldiaphragm into full spherical surface engagement with the undersurface of the vessel. Thereafter, when valves 3.2 are closed and valves 28 opened, the diaphragms assume an intermediate state of deflection to a degree dependingupon the pressure differentials between Vthe chambers 22 and 23.

We claim:

1. Apparatus for eliminatingv pulsations in a liquid stream flowing continuously through a line, comprising a housing, a pair of vessels contained in said housing, means connecting said vessels with said line at spaced locations therealong, said vessels containing gas which compresses and exin said housing, means connecting said vessels' with said line at spaced locations therealong, said v vessels containing gas which compresses and expands in response to increasing and decreasing pressures transmitted through the liquid from said line, and an elongated tube forming a restricted passage in the line between said locations.

3. Apparatus for eliminating pulsations in a liquid stream flowing continuously through a line, comprising a housing, a pair of vessels contained in said housing, means connecting said vessels with said line at spaced locations therealong, said vessels containing gas which compresses and expands in response to increasing and decreasing pressures transmitted through the liquid from vsaid line, means providing a restriction in' said line between said locations, valve means in the housing for closing communication between the line and said vessels, and means for withdrawing liquid from the vessels with said valve means closed.

4. Apparatus for eliminating pulsations in a liquid stream flowing continuously through a line comprising a housing, a pair of vessels containedr in the housing, each vessel containing a diaphragm and at one side of the diaphragm a chamber containing gas which compresses and expands in response to deflections of the diaphragm, means connecting said vessels at the other sides of their diaphragms with said line at, spaced locations therealong, and means provid-,. ing a restriction in the line between'said locations.

5. Apparatus for eliminating pulsations in a, liquid stream flowing continuously through a line, comprising a housing, a pair of vessels contained in the housing, each vessel containing a diaphragm and at one side of the diaphragm a chamber containing gas which compresses and expands in re-A sponse to deflections of the diaphragm, means connecting said vessels at the other sides of theirdiaphragms with said line at spaced locations therealong, means providing a restriction in the line between said locations, and fittings carried by said vessels at locations accessible at the outside of the housing for charging gas under pressure into said chambers.

6. Apparatus for eliminating pulsations in a liquid stream flowing continuously through aline, comprising a housing, a pair of vessels contained in the housing, each vessel containing a dia. phragm and at o ne nside of the diaphragm a chamber containing gas which compresses and expands in response to deflections of the diaphragm,- spaced pipes extending through the side of said housing and connecting said vessels at the other side of their diaphragms with said line, and an longer than the distance between said pipes.

7. Apparatus for eliminating pulsations in a liquid stream flowing continuously through a line,

comprising a housing, a pair of vessels contained in the housing, each vessel containing a dia-'` phragm and at one side of the diaphragm a chamber containing gas which compresses and expands in response to deflections of the diaphragm, spaced pipes extending through the side of said housing and connecting said vessels at the other side of their diaphragms with said line, an elon-- gated tube contained in the housing and connecting said pipes and forming a restricted passage in the line, said tube being longer than the distance between said pipes. fittings carried by said vessels and accessible from the outerends of the housing for charging gas under pressure into said chamber, valves in the housing for closing oommunicavrcn between said vessels and pipes, and valve controlled means operable when said valves are closed to withdraw liquid from said vessels.

containing gas which compresses and expands in liquid stream flowing continuously'through aline, 1

comprising a pair of vessels eachcontaining a diaphragm and at one :ide of the diaphragm a closed chamber containing gas which compresses and expands in response to deflections of the diaphragm, pipes connecting said vessels at the y other sides of their diaphragms with locations along said line, means restricting the liquid ow in the line between said locations, andnormally open valves in said pipes for closing communication between said vessels and line.

l0. Apparatus for eliminating pulsations in a liquid streamiiowing continuously through a line,

comprising a pair of vessels each containing a diaphragm and at one side of the diaphragm a closed chamber containing gas which compresses and expands in response to deflections of the diaphragm, pipes connecting said vessels at the other sides of their diaphragms with' locations along said line, means restricting the liquid flow in the line between said locations, normally open valves in said pipes for closing communication between said vessels and line, and means for withdrawing liquid from said vesselsv when said valves are closed.

1l. Apparatus for eliminating pulsations in a iiuid stream flowing continuously through a line,

comprising a shell containing a pair of chambers, means forming passages for connecting said chambers with said line at spaced locations therealong, said chambers being substantially closed except for said connections and containing gas which compresses and expands in response to in# creasing and decreasing pressures transmitted through said passages from the fluid in said line, and an elongated pipe contained in said shell and forming a restricted passage in the line between said locations, saidA pipe being substantially longer than the distance between said locations.

FOSTER. M. STEPHENS.

CECIL F. YATES.

REFERENCES CITED The following references are of record in file of this patent:

UNITED STATES PATENTS the 

